[PATCH] x86_64: Proper null pointer check in powernow_k8_get

This prevents crashes on dual core system when enough ticks are lost.

Replaces earlier patch by me.

Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 10 insertions, 1 deletions

diff --git a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
index 6ba497c47df6..7c0e160a2145 100644
--- a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
+++ b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
@@ -46,7 +46,7 @@
 
 #define PFX "powernow-k8: "
 #define BFX PFX "BIOS error: "
-#define VERSION "version 1.60.1"
+#define VERSION "version 1.60.2"
 #include "powernow-k8.h"
 
 /* serialize freq changes  */
@@ -910,6 +910,9 @@ static int powernowk8_target(struct cpufreq_policy *pol, unsigned targfreq, unsi
         unsigned int newstate;
         int ret = -EIO;
 
+        if (!data)
+                return -EINVAL;
+
         /* only run on specific CPU from here on */
         oldmask = current->cpus_allowed;
         set_cpus_allowed(current, cpumask_of_cpu(pol->cpu));
@@ -969,6 +972,9 @@ static int powernowk8_verify(struct cpufreq_policy *pol)
 {
         struct powernow_k8_data *data = powernow_data[pol->cpu];
 
+        if (!data)
+                return -EINVAL;
+
         return cpufreq_frequency_table_verify(pol, data->powernow_table);
 }
 
@@ -1103,6 +1109,9 @@ static unsigned int powernowk8_get (unsigned int cpu)
         if (!data)
                 return -EINVAL;
 
+        if (!data)
+                return -EINVAL;
+
         set_cpus_allowed(current, cpumask_of_cpu(cpu));
         if (smp_processor_id() != cpu) {
                 printk(KERN_ERR PFX "limiting to CPU %d failed in powernowk8_get\n", cpu);